The invention relates to a gas distribution assembly comprising a gas cylinder, particularly a medical gas cylinder, a valve unit, with or without an in-built regulator system, fixed to the gas cylinder, and a protective cap arranged around the valve unit to protect it from knocks and dirt.
Industrial and medical gases are commonly packaged at high pressure into gas containers, typically gas cylinders, equipped with a valve unit which may or may not incorporate an in-built regulator, namely a simple valve of the open/closed type or a valve with an in-built regulator, also referred to as a regulator valve RDI, so that the flow rate and pressure of the gas delivered can be controlled.
In order to protect this valve unit it is commonplace to fit around the said valve unit a protective cap that forms a protective shell around the body of the valve. Such a cap is often referred to as a “bonnet”. Caps of this type are described notably in documents EP-A-629812, DE-A-10057469, US-A-2004/020793 and EP-A-2586481.
Control of the flow of gas through the valve unit is usually had via a gas-passage control system arranged on the internal gas passage which fluidically connects the gas container to an output orifice of the valve unit, the said gas-passage control system generally collaborating with a control member that can be operated by a user, typically a rotary handwheel.
It has been found in practice that while the protective cap affords the body of the valve unit good protection against knocks, it does not do the same for the rotary handwheel when the latter is arranged on the front or on one of the lateral faces of the cap and/or of the valve unit.
What happens is that the rotary handwheel can easily be damaged if the cylinder falls onto the ground because it generally extends beyond the surface of the cap and is therefore exposed if the cylinder falls over or if two cylinders bang together when stored side by side.
Document EP-A-1013986 proposes a protective cap for a gas cylinder comprising a wide opening on the front face thereof, which opening provides access to the various components of the valve around which it is arranged. Such a solution is not ideal since, because of the wide opening made in the cap, dust or the like can enter the cap, presenting problems of hygiene, particularly when the cylinder is to be used in a hospital or similar environment.
In addition, although incorporating into the cap the handwheel that controls the release of the flow rate of gas provides it with protection against falls, a problem of precise adjustment of the gaseous flow rate and of reading the selected flow rate value arises.
Alternative solutions are given in documents U.S. Pat. No. 5,099,567, U.S. Pat. No. 4,600,033, WO-A-2008/149312 and US-A-2009/0038691. However, none of these is truly satisfactory because they all present problems which are notably identical or similar to those mentioned hereinabove.
The problem that arises is that of improving the protection of the rotary handwheel with which the valve unit of a gas distribution assembly is equipped, this gas distribution assembly comprising a gas cylinder, a valve unit, with or without an in-built regulator system, fixed to the gas cylinder, and a protective cap arranged around the valve unit, in which distribution assembly control over the release of the flow of gas is had by means of a control member of the rotary handwheel type that can be operated by a user, while at the same time affording the valve elements good protection and guaranteeing a level of hygiene compatible with use in the health domain in particular.